Home > Publications database > Katalytische Konversion von $^{11}CO_{2}$ und $^{11}CO$ zu Synthesevorläufern für $^{11}C$-Markierungen |
Book/Report | FZJ-2018-06509 |
1994
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/20091
Report No.: Juel-2881
Abstract: The positron emitter carbon-11 (T$_{1/2}$ =20.3 min) is an ideal radio nuclide for tracers in positron emission tomography (PET). In this study catalytic methods for the synthesis of [$^{11}$C]alcohols have been investigated. The formation of [$^{11}$C]methanol has been studied on Pd/Al$_{2}$O$_{3}$ and Cu/ZnO/Al$_{2}$O$_{3}$ catalysts with respect to CO and CO$_{2}$ carrier addition to the synthesis gas. Carbon monoxide was identified as the precursor of methanol formation on the Pd/Al$_{2}$O$_{3}$-catalyst. In contrast on the Cu/ZnO/Al$_{2}$O$_{3}$-catalyst methanol was formed on a reaction pathway via an adsorbed CO$_{2}$-species. A n.c.a.-[$^{11}$C]methanol synthesis basing on the Cu/ZnO/Al$_{2}$O$_{3}$-catalyst has been developed by substitution of the oxygen containing components CO and CO$_{2}$ in the synthesis gas by N$_{2}$O. The radiochemical yield, the low selectivity of [$^{11}$C]methanol production and the rather slow kinetics of this process were arguments against the practical use of this process in the synthesis of $^{11}$C-Iabelling agents. A new method for the n.c.a.-synthesis of higher [$^{11}$C]alcohols using Wilkinson's catalyst [P(C$_{6}$H$_{5}$)$_{3}$]$_{3}$ described. The product of the reaction of $^{11}$CO and [P(C$_{6}$H$_{5}$)$_{3}$]$_{3}$RhCl, n.c.a.-trans-[P(C$_{6}$H$_{5}$)$_{3}$]$_{2}$Rh($^{11}$CO)Cl, is reacted with alkyliodide and M$^{+}$[B(OR)$_{3}$H]$^{-}$ yielding the [$^{11}$C]alcohol in high specific activity and high radiochemical yield.
The record appears in these collections: |